The butterfly bush (Buddleia species) is a traditional old-fashioned favorite beloved by many.
Buddleias are ideal flowering shrubs with many excellent qualities, and for continuous flower from July to October, they are without equal. Butterfly bushes grow rapidly, have attractive woolly or smooth foliage, are richly scented and are easy to grow and care for. They grow from 2-15 feet tall, produce wonderful flower spikes of white to pink to purple (as well as yellow) and are hardy in zones 5-10.
As the name implies, butterfly bushes attract butterflies (and hummingbirds!) - often in astronomical quantities! Because butterfly bushes are so dense and versatile, there is sure to be one to fit into almost any garden!
CULTURAL REQUIREMENTS
Buddleias are very forgiving plants. They tolerate any well draining soil - lean, rich, mildly acidic or alkaline. Although they flower best in full sun, they bloom well in light or filtered shade. Variegated types should be grown only in shade since full sun will scorch the leaves. Most buddleias tolerate drought.
PRUNING
If never pruned, some butterfly bush cultivars may reach up to 15’ in height. But leaving butterfly bushes un-pruned is NOT recommended. Buddleias need proper pruning and deadheading to sustain maximum flowering and to prevent them from literally ‘flowering themselves to death.’ How and when to prune and deadhead depends on the type your grow and your climate.
The most popular type of butterfly bush is Buddleia davidii - the ‘orange-eyed’ butterfly bush. This buddleia produces flowers on new wood - or shoots that will be produced in the current year.
Buddleias davidii is often very slow to show signs of life in the spring. This is normal. Do not panic if your butterfly bush does not appear to be growing. When warm temperatures arrive it will rapidly catch up with other shrubs and trees in your yard.
In our Zone 6, we recommend that ‘orange-eyed’ butterfly bushes be cut back to about 10 inches tall each spring before new growth begins (or by 1/2 for dwarf types). This hard pruning will result in better foliage, larger flowers and increased longevity for your plant. After this initial cut, feel free to prune as heavily as needed during the growing season to control shape and size; flowering will not be affected because new buds are constantly being formed. As flowers fade, be sure to deadhead to encourage new shoot and flower growth.
NOTE: Another less popular type of butterfly bush, Buddleia alternifolia (fountain Butterfly Bush) forms flower buds on old wood - or shoots produced in the previous year. This type of buddleia should not be pruned in early spring. Instead, prune lightly immediately after bloom period in late spring.
FERTILIZER
Newly planted butterfly bushes should only be fertilized with a starter fertilizer/root stimulator such as UpstartTM. Fertilize at planting time and once a month up through August. Thereafter, fertilize
established buddleias each spring as soon as new shoots appear. Avoid over-fertilization, for if treated too well, buddleias produce large amounts of soft shoot growth at the expense of both flowering and hardiness. Try a slow-release fertilizer, such as Osmocote, to promote early shoot and leaf
development without delaying flower formation.
DISEASES AND PESTS
Buddleia davidii cultivars are relatively trouble-free and have no major diseases. The only notable insect pest is the two-spotted mite, which can render leaves speckled gray-green. Healthy unstressed, vigorous garden plants that are sited properly have minimal problems. (Please avoid use of chemical insecticides, they are highly toxic to butterflies and hummingbirds! Learn to appreciate natives beautiful creatures and overlook slight plant imperfections).
USE
Butterfly bushes can fill a variety of garden landscape niches. Butterfly bushes are great in groupings, as background plants in the herbaceous border or mixed with other shrubs. Their wonderful fragrance makes them a superb plant to enjoy near patios or other outdoor living areas. In a sunny garden spot, butterfly bushes will be the focal point of a butterfly garden with lantanas, verbenas, spireas, salvia and other butterfly favorites. Try training butterfly bushes into small, mop-headed trees or espalier them onto a fan trellis. Consider planting a butterfly bush as a nostalgic heirloom and tribute to the good old days! Use dwarf varieties in rock gardens and as ground covers!
SPECIES AND CULTIVARS
Buddleia davidii - Cultivars of this buddleia are among the most popular and easy to find. They have a wide color range of white to all shades of lavender and purple. Hardy to Zone 5, they can reach 3 to 15 feet, depending on variety. Larger cultivars are informal spreading shrubs best suited for the back of the border. Compact varieties are great for massing, edging or ground cover. Leaves of all cultivars are dark green or blue gray with felted undersides.
This type of buddleia can retain a significant portion of its foliage over the winter. Flower fragrance
varies in strength from cultivar to cultivar. Flowers appear on spikes 6-30 inches long! The largest flowers are produced early in the season on new vigorously growing shoots. Later flowers are
generally smaller, but cultivar, degree of pruning, water and fertility will all strongly regulate the size of the spikes. Bloom time is July to frost. Prune back to 10 inches in early spring.
Buddleia alternifolia - The ‘fountain’ butterfly bush has a graceful weeping habit. It has inch wide
lavender flower clusters arranged along the previous years stems. This Buddleia type flowers only once a year in late spring, but does so for a long 4-6 week period. It is a bit hardier than orange-eyed butterfly bush. Since B. alternifolia can grow 10 to 15 feet tall, use it as a specimen plant or give it room at the back of the border. Both the species and a silver-leaved cultivar can be trained to a single stem, using a stake for support, to enhance the fountain-like appearance. They also can be espaliered in a fan shape to a south-facing wall. Prune back lightly immediately after flowering.